The geniuses of The Big Bang Theory get thrown for a bell curve in all 24 episodes of the phenomenally funny fifth season of the hit show. Penny and Leonard's relationship is relaunched in full "beta test" mode, while Sheldon, Howard, and Raj discover the feminine mystique is something that cannot be easily graphed or calculated. As Sheldon makes begruding admendments to his "Relationship Agreement" with his "Friend-who-happens-to-be-a-girl" Amy Farrah Fowler. Raj contemplates an arranged marriage, and Howard is all-systems-go for both his NASA space launch and wedding to the spirited Bernadette.

1. The Skank Reflex Analysis
When Penny and Raj come out of Leonard's bedroom togther, accusations fly and a friendly paintball tournament becomes a chance to get the guys' feelings out in the open.

2. The Infestation Hypothesis
While Leonard tries to maintain his long-distance relationship with Priya, Penny takes in a chair she found on the street, to Sheldon and Amy's absolute horror.

3. The Pulled Groin Extrapolation
Jealousy is in the air when Amy asks Leonard to escort her to a wedding, and Howard discovers that Bernadette may be a too-close-for-comfort version of his mother.

4. The Wiggly Finger Catalyst
While Penny sets up Raj with his dream girl, Sheldon relies on Dungeons and Dragons dice to make some seemingly minor decisions.

5. The Russion Rocket Reaction
Emotions run sky-high when Sheldon discovers that Leonard plans to attend Wil Wheaton's party, and Howard ponders an opportunity to work on the International Space Station.

6. The Rhinitis Revelation
Sheldon's mother comes for a visit, and he finds himself in the awkward position ofhaving to share her attentions with his friends.

7. The Good Guy Fluctuation
Scares are everywhere as Leonard admits to Priya that he's attracted to someone else, and Sheldon pulls a slew of Halloween pranks on his friends.

8. The Isolation Permutation
Amy's feelings are hurt when Penny and Bernadette go dress-shopping without her, and Sheldon's attempts to help just aggravate the situation.

9. The Ornithophobia Diffusion
It's time for facing fears head-on when Leonard and Penny attempt to be together just as friends, and Sheldon must deal with a bird camping out in the living room.

10. The Flaming Spittoon Acquisition
When Stuart asks Amy out on a date, Sheldon must make a big decision regarding his feelings for her.

11. The Speckerman Recurrence
Old feelings from high school resurface when a former bully askes Leonard to meet for a drink, and Penny realizes she wasn't the nicest person back then either.